U.S. Pat. No. 3,444,620 discloses a device for shearing the needle or cannula adjacent to the hub of an attached syringe by rotating a shearing member, having a cavity into which a syringe has been inserted, around a transversely disposed stationary shearing member having a connected cavity enclosing the cannula, whereby shearing edges at the connection of the cavities sever the cannula. However, there is no provision for severing or destroying any part of the syringe which may also be contaminated. Furthermore, the rotatable shearing member is rotated by using the exposed portion of the syringe as a handle, which would furnish an amount of leverage unlikely sufficient to shear the hub of a syringe should shearing edges be provided for that purpose.
Certain prior destructor devices provided shearing mechanism operated by squeezing hand levers together, as exemplified by U.S. Pat. No. 4,255,996. However, the squeezing force required to shear a syringe in this manner is quite substantial with the result that older hospital personnel found it increasingly difficult, especially if a number of syringes are cut at one time. Moreover, such devices usually embody a pivoted scissor-like design and the wearing and loosening of the pivot as well as dulling of the blades shortens the useful life of the device.
Further, such devices require opening to empty the cut-off parts, and while opened the contents are frequently spilled into a hospital environment where they are an obvious hazard by accidental transmission of dangerous diseases such as hepatitis.